Sometimes the jokes write themselves. From today's student newspaper on my campus:

Second, they deny that life begins at conception. Every human whether alive or aborted, has been conceived. This first step in life’s process cannot be skipped, if it cannot be skipped and it’s the first step, then it must mean that it’s important and that it’s the beginning. Life begins at conception!

Welcome to the world of the post hoc fallacy. A biological process (sperm meeting egg) precedes another (fetus developing into a viable human life) therefore they are one and the same. Like how eating precedes shitting, and therefore eating is shitting.

Post hoc fallacies are among the oldest flaws in human reasoning, dating back to the days when cavemen banged on drums to make the sun come up. Every morning was a sign that it was working. A post hoc fallacy is any argument that looks at two events in a timeline and assumes that the earlier is either causal to or an integral part of the latter.

I hesitate to play the slippery slope game, but indulge me for a moment as I extend the reasoning used in the example above. We can't have life without conception, so conception is life. Well, we can't have conception without sex. Does life begin at sex? We can't have procreative sex without a male and female meeting one another. Does life begin when they meet? Men and women don't meet each other unless they make an effort to socialize. Does life begin when you decide to go to a party on the weekend?

I'm getting a little ridiculous here but not much more ridiculous than any other post hoc argument. Things that happen in a sequence are not necessarily causally related, and things that are causally related do not magically become the same thing. I wonder if it ever occured to the "Life begins at conception!" crowd that many people are not persuaded by the argument because it makes absolutely no sense. No, it's always that we liberals are misguided, uninformed, or wicked sodomites who hate Jesus. Demonizing one's opponents ("Anti-life!") because they refuse to be persuaded by fallacious arguments is…well, that's just the greatest recipe for political success I've ever heard. Good luck with that.

9 thoughts on “ED vs. LOGICAL FALLACIES, PART 18: POST HOC”

  • At one time various religions didn't do a naming ceremony until the kid was about a year old and they were pretty sure would survive. See what modern technology has done, now they call it life at conception and are ready to name it as soon as the sex is determined.

  • Their argument does not seem like post hoc. In fact B (human) can not happen without A (conception) having taken place. All the activities you mention in your extended reasoning are not required to produce life.

    You could, however, still argue that they reach their conclusion fallaciously by providing a definition of life, and then describing why B fits that definition while A does not.

  • Abortion is something that I really, really, struggle with.

    But I also think that the argument over where "life begins" is secondary to the abortion argument. At the end of the day, I don't necessarily buy the argument that abortion is ok because life doesn't start at conception. If, in fact, we believe that a woman has the right to control her reproductive organs, doesn't it follow that the woman's rights would supercede the rights of an embryo? It may seem harsh, but if we start to argue over where life begins, we lose sight of the whole argument of whether a woman must always, under all circumstance, continue a pregnancy to term – that the right of a fertilized egg to develop into a human being is greater than any contrary desire on the part of the woman.

    I believe that what really, really drives the abortion argument for many people is not a concern for the sanctity of life. I think it's about controlling sexual behavior. Everyone I know who is "pro-life" frames their argument by saying something along the lines of, "Women who just think they can sleep around and then kill their baby because it's inconvenient are going to hell…" I think that's why you almost never hear about an alternative to abortion other than celibacy. It's why, as a gay man, I think it is critically important to support reproductive rights.

    I could go all day. But to your point, I agree that the article you reference is poorly reasoned. Love the blog.

  • I must agree with Michael. The argument about when life "begins" is an unanswerable sideshow to the real issue. My real complaint about the pro-lifers is that they have a tendency to vastly underestimate the complexity of the situation. Our government cannot even get the simple things right – can we really have confidence that a tiny portion of the population comprised mainly of a bunch of old foolish twits could really create legislation that does this complex issue justice? I would much rather leave such difficult decisions to those closest to the issue. Some women will make bad decisions – but let us not lose sight of the multitude of coat-hangers present in today's society.

  • Michael raises the important issue of "hell," which to me is the reason why the "life starts at conception" argument is fundamentally witless; it's foolish because it's an attempt to frame a religious question scientifically. Like "intelligent design" arguments, which are inevitably, painfully illogical no matter how artfully phrased, "life begins at conception" is the way people with a religious objection to a scientific practice try to shift their objection to a supposedly 'faith-neutral' ground:

    "See? We're not saying this because we believe in a strict doctrine of reasonless faith! We're saying this because we stand on good, sound reason–this isn't about 'the soul' or 'sin', it's about the scientific process of life! So, see? We can engage in debate that won't force us to concede that we're doing this because we think that doing certain things makes Baby Jesus cry!"

    But that's crap, and phrases like "the *sanctity* of life" reveal it to be so. It *is* a spiritual debate for them, because they do not believe that humanity is defined by consciousness, but by its 'soul.' Which is pretty much the end of the discussion, and why each side needs to stop trying to co-opt the language of the other.

  • Picking on a student newspaper for logical fallacies, Ed? That's like playing basketball with a retarded kid and calling him for double dribble.

  • I recently interviewed with the chair of a University journalism department vis-à-vis enrolling in his program. We engaged in a lively little chat about ethics and quality and such. I had a pretty good warm and fuzzy going until an hour later when I grabbed a copy of the student paper. Needless to say I'm no longer considering that avenue.

  • This isn't a post hoc fallacy, it's circular reasoning.

    "Every human whether alive or aborted, has been conceived."
    – Assuming that the fetus is human, i.e. that at conception, they're alive (note, I agree here, but they're argument is horrible and that's all I feel like talking about right now)

    "This first step in life’s process cannot be skipped,"
    – Same basic assumption, that conception is the first step in life, i.e., life begins at conception.

    " if it cannot be skipped and it’s the first step, then it must mean that it’s important and that it’s the beginning. "
    – Saying that since it's the first step, so it's the beginning is just a tautology (true strictly by it's logical form). "it's the beginning" and "it's the first step" both mean that "life begins at conception." They're statement here is "life begins at conception" implies that "life begins at conception."
    A circular argument within their larger, circular argument.

    They're argument isn't an ad hoc fallacy, there was no causal relationship argued for here at all. They stated their conclusion, then stated it again, then stated that their conclusion implies that their conclusion is true, and finished off by saying that all of this means their conclusion is true. Hell, this barely qualifies as a circular argument now that I've written it all out. They just stated their conclusion over and over again.

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